1 /**************************************************************************
2 *
3 * Copyright 2017 Valve Corporation
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28 /* Allocator of IDs (e.g. OpenGL object IDs), or simply an allocator of
29 * numbers.
30 *
31 * The allocator uses a bit array to track allocated IDs.
32 */
33
34 #ifndef U_IDALLOC_H
35 #define U_IDALLOC_H
36
37 #include <inttypes.h>
38 #include <stdbool.h>
39 #include "simple_mtx.h"
40
41 #ifdef __cplusplus
42 extern "C" {
43 #endif
44
45 struct util_idalloc
46 {
47 uint32_t *data;
48 unsigned num_elements; /* number of allocated elements of "data" */
49 unsigned lowest_free_idx;
50 };
51
52 void
53 util_idalloc_init(struct util_idalloc *buf, unsigned initial_num_ids);
54
55 void
56 util_idalloc_fini(struct util_idalloc *buf);
57
58 unsigned
59 util_idalloc_alloc(struct util_idalloc *buf);
60
61 unsigned
62 util_idalloc_alloc_range(struct util_idalloc *buf, unsigned num);
63
64 void
65 util_idalloc_free(struct util_idalloc *buf, unsigned id);
66
67 void
68 util_idalloc_reserve(struct util_idalloc *buf, unsigned id);
69
70 static inline bool
util_idalloc_exists(struct util_idalloc * buf,unsigned id)71 util_idalloc_exists(struct util_idalloc *buf, unsigned id)
72 {
73 return id / 32 < buf->num_elements &&
74 buf->data[id / 32] & BITFIELD_BIT(id % 32);
75 }
76
77 #define util_idalloc_foreach(buf, id) \
78 for (uint32_t i = 0, mask = (buf)->num_elements ? (buf)->data[0] : 0, id, \
79 count = (buf)->num_elements; \
80 i < count; mask = ++i < count ? (buf)->data[i] : 0) \
81 while (mask) \
82 if ((id = i * 32 + u_bit_scan(&mask)), true)
83
84
85 /* Thread-safe variant. */
86 struct util_idalloc_mt {
87 struct util_idalloc buf;
88 simple_mtx_t mutex;
89 bool skip_zero;
90 };
91
92 void
93 util_idalloc_mt_init(struct util_idalloc_mt *buf,
94 unsigned initial_num_ids, bool skip_zero);
95
96 void
97 util_idalloc_mt_init_tc(struct util_idalloc_mt *buf);
98
99 void
100 util_idalloc_mt_fini(struct util_idalloc_mt *buf);
101
102 unsigned
103 util_idalloc_mt_alloc(struct util_idalloc_mt *buf);
104
105 void
106 util_idalloc_mt_free(struct util_idalloc_mt *buf, unsigned id);
107
108
109 #ifdef __cplusplus
110 }
111 #endif
112
113 #endif /* U_IDALLOC_H */
114